Baltimore’s top prosecutor filed a petition Thursday to vacate nearly 4,000 convictions for marijuana possession, saying the rare move is necessary to “right an extraordinary wrong.”

State’s Attorney Marilyn Mosby employed a rarely used petition called “writ of error coram nobis,” according to the Associated Press. The petition allows a court to reopen a case when significant error is found that was not uncovered during the original judgement. If granted, the petition could overturn 3,778 convictions. 

{mosads}“The sordid history of marijuana prohibition lies in ethnic and racial bigotry,” Mosby wrote in the petition, noting the continued racial disparities in drug-related arrests.

The petition comes two days after Mosby announced it will no longer prosecute any cases related to marijuana possession, regardless of quantity or a person’s criminal record.

“No one who is serious about public safety can honestly say that spending resources to jail people for marijuana use is a smart way to use our limited time and money,” she said Tuesday.

Mosby said her office will instead focus on prosecuting dealers and traffickers in marijuana distribution cases. 

While Baltimore’s mayor said she was supportive of Mosby’s actions, Interim Commissioner Gary Tuggle said police officers would continue to make arrests for marijuana possession based on state law.

Maryland decriminalized possession of 10 grams or less of marijuana in 2014, instead handing out fines. Two years later, the state also decriminalized the smoking of marijuana in public and the possession of paraphernalia.

Nationally, the District of Columbia and ten states have already legalized the recreational use of marijuana, while 23 other states have laws in place legalizing medical pot.